Exclusive Control

@Component
@Scope("step")
public class FileExcusiveTasklet implements Tasklet {

    private String targetPath = null; // (1)

    @Inject
    ItemStreamReader<SalesPlanDetail> reader;

    @Inject
    ItemStreamWriter<SalesPlanDetailWithProcessName> writer;

    @Override
    public RepeatStatus execute(StepContribution contribution,
            ChunkContext chunkContext) throws Exception {

        // omitted.

        FileChannel fc = null;
        FileLock fileLock = null;

        try {
            reader.open(executionConetxt);
            writer.open(executionConetxt);  // (2)

            try {
                File file = new File(targetPath);
                fc = FileChannel.open(file.toPath(), StandardOpenOption.WRITE,
                        StandardOpenOption.CREATE,
                        StandardOpenOption.APPEND); // (3)
                fileLock = fc.tryLock();  // (4)
            } catch (IOException e) {
                logger.error("Failure other than lock acquisition", e);
                throw new FailedOtherAcquireLockException(
                        "Failure other than lock acquisition", e);
            }
            if (fileLock == null) {
                logger.error("Failed to acquire lock. [processName={}]", processName);
                throw new FailedAcquireLockException("Failed to acquire lock");
            }

            // (5)
            SalesPlanDetail item;
            List<SalesPlanDetailWithProcessName> items = new ArrayList<>();
            while ((item = reader.read()) != null) {

                // omitted.

                items.add(item);
                if (items.size() >= 10) {
                    writer.write(items);
                    items.clear();
                }
            }
            if (items.size() > 0) {
                writer.write(items);
            }

        } finally {
            if (fileLock != null) {
                try {
                    fileLock.release();  // (6)
                } catch (IOException e) {
                    logger.warn("Lock release failed.", e);
                }
            }
            if (fc != null) {
                try {
                    fc.close();
                } catch (IOException e) {
                    // ignore
                }
            }
            writer.close(); // (7)
            reader.close();
        }
        return RepeatStatus.FINISHED;
    }

    // (8)
    @Value("#{jobParameters[outputFile]}")
    public void setTargetPath(String targetPath) {
        this.targetPath = targetPath;
    }
}